package cn.com.zero.web.util;

import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;

/**
 * @author xiongxj
 * @version 1.0.0
 * @Description http请求的工具类
 * @createTime 2022/7/13 15:13
 */
public class HttpRequestUtil {

    private static final String UNKNOWN = "unknown";

    /**
     * 获取 Request
     *
     * @return HttpServletRequest 本次访问的 Request信息
     */
    public static HttpServletRequest getRequest() {
        return getRequestAttributes().getRequest();
    }

    /**
     * 通过key值从请求头中获取值
     *
     * @param key key值
     * @return 请求头中对应的值
     */
    public static String getHeader(String key) {
        String value = getRequest().getHeader(key);
        if (value == null) {
            return "";
        }
        return value;
    }

    /**
     * 获取客户端 IP 地址<br/>
     * 使用 Nginx等反向代理软件， 则不能通过 request.getRemoteAddr()获取 IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，
     * X-Forwarded-For中第一个非 unknown的有效IP字符串，则为真实IP地址
     *
     * @return String 客户端 IP 地址
     */
    public static String getRequestIp() {
        HttpServletRequest request = getRequest();
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : ip;
    }

    /**
     * 获取 Request存放对象
     *
     * @return ServletRequestAttributes Request存放对象
     */
    public static ServletRequestAttributes getRequestAttributes() {
        RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
        return (ServletRequestAttributes) attributes;
    }
}
